MLA

Brush, George Jarvis, 1831-1912. Eliot, Charles William (50). Box 2, folder 44. 1860-1863, 1865, 1867-1869, 1871-1872, 1875, 1877, 1882-1883, 1886-1889, 1891, 1893, 1896-1897, 1899, 1901-1902, 1912, undated. https://collections.library.yale.edu/catalog/32512827.

APA, 6th edition

Brush, George Jarvis, 1831-1912. (["Box 2, folder 44"])(1860-1863, 1865, 1867-1869, 1871-1872, 1875, 1877, 1882-1883, 1886-1889, 1891, 1893, 1896-1897, 1899, 1901-1902, 1912, undated)[Eliot, Charles William (50)]. https://collections.library.yale.edu/catalog/32512827.